Background

When navigating a complex world, we often form memories of similar events. This can lead to interference, or confusion, between similar memories. Recent work has suggested that we may possess adaptive processes that allow us to better discriminate between these similar memories. Specifically, there may be “repulsion” where similar memories are remembered as more different than they actually are. However, those studies were limited to the measurement of one or two features (e.g., color). In this experiment, I seek to measure repulsion in memory for naturalistic scene images using more complex free verbal recall.

Conditions

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Example Competitive Stimuli

Example Non-Competitive Stimuli

Experimental Design

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Study Phase

Description

During the study phase, participants learn pairs of face images (cues) and scene images (associates). Trials begin with a face image (1000ms), followed by a fixation cross (500ms), then a scene image (3000ms), followed by a fixation cross (1000ms).

Sample Trial

Vividness Phase

Description

During the vividness phase, participants are presented with each face image cue, and must practice recalling the associated scene image as vividly as possible, and rate the vividness of their memory using a 3-point scale (vivid, weak, or no memory). Trials begin with a face image (1000ms), followed by a fixation cross (500ms). Then a black box is presented (1500ms) as a cue to recall the associated scene image, followed by a red box (1500ms) as a cue to make a keyboard response on vividness of the memory (‘j’ = vivid, ‘l’ = weak, ‘l’ = no memory). The trial ends with a fixation cross (1000ms).

Sample Trial

Recall Task

Description

During the recall phase, participants view each face image cue one at a time. They must recall the associated scene image and type a description of the scene image in at least 10 words. If they do not remember the associated scene image, they may check the box to indicate they do not remember.

Sample Trial

Analysis

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Number of Words

Description

Distribution of number of words used to describe scene images in the competitive and non-competitive conditions.

Figure

Remembered Information

Description

Text embeddings from the competitive and non-competitive conditions are correlated with text embeddings for same-category text embeddings from the non-competitive condition. Lower correlations indicate a “repulsion” effect, where an image is remembered as more different from other same-category images. Indeed, correlations from the competitive condition were significantly lower than the non-competitive condition, indicating a “repulsion” effect when same-category images are studied together, Welch’s t(75.31) = 3.87, p < 0.001.

Figure